The Tootsie star admits he had been putting off the idea of stepping behind the camera for years, but he knew he'd have no problems re-energising his cast when he made his debut - thanks to lessons learned.

He explains, "Mike Nichols... said to me one day when I was a little tired, he took me aside and he said, 'This is the only time you're ever gonna have the chance to do this scene, and it's gonna be up there for the rest of your life so feel like you've given it more than your all.'"

Hoffman put the lesson to good use when Dame Maggie Smith, who portrays an ageing former opera star in Quartet, was struggling to understand one particular scene - he asked the veteran Brit to channel her inner diva.

He reveals, "I sent the crew out, sat her down and we had a long talk. I believe all good work has to be autobiographical so I said, 'Maggie, this is not a character, this is you.' We're both in our 70s and I want to know what that feels like for you... I'd found an interview she'd given, talking about being ill, getting old and her view of the future. I got her to say some of those same quotes in the film."

But it wasn't just Nichols' style of directing that Hoffman was inspired by - he was determined to create an amiable atmosphere on the shoot so his cast and crew would feel just as comfortable as he did on Barry Levinson's Rain Man set in 1988.

He adds, "Everyday we went to work, he (Levinson) would be sitting in a chair telling a story and (the crew) would say, 'We're ready'. He'd say, 'I'm not done with my story,' and would finish his story (first). He created an amiability and relaxation (on set)...

"I've been doing it (acting) for 45 years and I never understood... The idea is to feel loose and to feel like you're not shooting, you're rehearsing, basically."